Limitations and drawbacks of DQE estimation methods applied to electron detectors

Area of Science:

• Electron microscopy
• Detector physics
• Image quality assessment

Background:

• Detective quantum efficiency (DQE) is the primary metric for evaluating electron detectors.
• DQE is typically reported at the Nyquist frequency, despite its known dependence on electron dose.
• Current DQE estimation methods, like the one improved by McMullan (2009), may require critical analysis.

Purpose of the Study:

• To critically analyze and evaluate the prevalent DQE extraction method for electron detectors.
• To investigate the influence of electron dose on DQE measurements.
• To provide recommendations for standardized and fair comparisons between different electron detectors.

Main Methods:

• Analysis of measurement data from electron detectors.
• Application of theoretical models to understand DQE variations.
• Comparison of DQE values across different electron doses and detector types.

Main Results:

• The DQE is not a static value and significantly varies with electron dose.
• The commonly used DQE extraction method may not accurately represent detector performance under all conditions.
• Discrepancies were observed between model predictions and experimental measurements.

Conclusions:

• The DQE's dependence on electron dose necessitates a re-evaluation of its use as a single figure of merit.
• The current DQE estimation methodology may lead to inaccurate detector comparisons.
• Further research is needed to determine if DQE is the most appropriate metric for electron detectors or if alternative metrics are required.